Cartridge feeding mechanism for automatic guns



2 Sheets-Sheet 1 V C. T. HALL Fil ed Nov. 26, 1941 lllllllllllv Jan. 2,19 45.

C. T. HALL Jan. 2, 1945.

CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC GUNS Filed Nov. 26, 1941 2Sheets-Sheet 2 3 WMFMM PM Fen/5'02 Aria 1 72 (7y:

Patented Jan. 2, I945 CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC GUNSCharles Thomas Hall, Deptford, London, England, assignor to MolinsMachine Company Limited, Deptford, London, England 1 ApplicationNovember 26, 1941, Serial No. 420,570 In Great Britain January 21, 19411 Claim.

This invention is concerned with improvements in or relating tocartridge feeding mechanism for an automatic gun in which cartridges arefed in winding mechanism connected with said spring and adapted forrotation in one direction only and wherein a swinging member adapted tobe intermittently engaged and actuated by an actuating element movablewith a recoiling part of the gun is arranged intermittently to rotatesaid mechanism to effect reloading of the spring. Such feeding mechanismwill be referred to below as "cartridge feeding mechanism as specified.

In automatic guns fitted on aircraft where the feeding mechanism andbarrel are separately attached to the air frame, the relative movementbetween the gun barrel and the cartridge feeding mechanism frequentlyvaries considerably, and an object of the present invention is toprovide a cartridge feeding mechanism which will rotate the windingmechanism an effective constant amount after'each shot is fired, evenwhere the relative movement between barrel and feed mechanismis subjectto considerable variation as in the case just mentioned.

According to the invention there is provided acartridge feedingmechanism as specified, wherein a cam is provided on the swinging memberand has two portions which are capable of being engaged successively bythe actuating element, the first said portion of the-cam being inclinedto a radial line drawn from. the axis of the swinging member to thedriving side of said actuating-element and located between said axis andthe part of the actuating-element which engages the first said portionof the cam, the parts being so arranged that during a predeterminedinitial movement of the actuating-element the distance between thelatter and the axis of the swinging member is reduced, and wherein thelength of the first said portion of the cam is such that theactuating-element engages the junction between the two portions of thecam after the actuating-member has moved said predetermined distancerelatively to the cartridge feedin mechanism, the second cam face beingso arranged that any continued relative movement of the actuating memberwill cause a reduced swinging'movement of the swinging mem ber.

The winding mechanism may comprise a pair of co-operating bevelgear-wheels, one of which is connected with the spring and is mountedfor movement relatively to said "shaft, while the other of said bevelgear-wheel is mounted for rotation and is connected with a ratchet wheeloperable by said swinging member.

An embodiment of the invention will be described with reference to theaccompanying drawings which show the feeding mechanism for an automaticgun firing 20 m./m. projectiles.

In the drawings:

Figure 1 is an elevation partly in section of feedin mechanism,constructed according to the invention.

Figure 2 is an end elevation of Figure 1 looking in the direction of thearrow A.

Referring to the drawings the feeding mechanism is located above thebarrel I of th gun and comprises a substantially cylindrical casing 2having at one side an opening 3 through which a disintegrating beltcomprising clips 4 containing the cartridges 5 can pass, and at theopposite side of the breech a further opening 6 through which the emptyclips 4 may fall as indicated in Figure 2. The barrel of the gun isadapted to be slidably mounted on a support, not shown (e. g. theframework of an aircraft) so as to allow for recoil whilst thecylindrical casing 2 is fixedly mounted on the support as describedbelow, thus as the barrel recoils there is relative movement between thecylindrical casing and the gun-barrel in the direction of the axis ofthe gun-barrel and as indicated by the arrow B Figure 1.

The casing 2 has end plate I and 8attached thereto by bolts 9 and withinthe casing there is mounted for rotation a shaft In to which is secureda plurality of feeding elements consisting of sprockets II which areadapted to engage the cartridges and to feed them successively in toposition above the breech of the gun. The shaft is rotated by a loadedspiral spring l2. the outer end of which is secured to a casing i 3fixed to one of the feeding elements II. In operation this spring ispre-loaded to a desired tension in readiness for the gun to be fired.The other or inner end of the spiral spring is secured to a sleeve l4mounted for rotation about said shaft and arranged to be movablerelatively to the shaft in an angular direction. As the mechanismoperates to feed a cartridge into position above the breech of the gun,the spring is partly unwound or unloaded as each cartridge is fed. .Inthe example given, the spring is partly unloaded to the extent of A1 ofa complete tum. If it is desired that the feeding mechanism shall remaineffective for an-indefinite period, it is necessary secured a ratchetwheel IS. The ratchet wheel.

is rotated step by step due to the recoil of the gun-barrel in themanner described below. A spring urged stop pawl 20 is provided toprevent the ratchet wheel, and consequently the'bevel gear wheels, frombeing rotatedin the reverse T direction.

To effect the rotation of the ratchet wheel, a swinging member or lever2| is provided and freely mounted on the spindle If! to which theratchet wheel is secured and the swinging member supports a pawl 22which is spring urged by a spring 23 towards the ratchetwheel. Theswinging member is provided with cam faces 24 and 29 with which a camroller or actuator element 25 supported on a bracket 26 attached to thegun barrel, co-operates. A spring 21 is pro-' vided to urge the swingingmember towards the cam roller. As the gun-barrel recoils, the swin ingmember is caused to rotate about the spindle H with the result that thepawl carried by the swinging member rotates the ratchet wheel one tooth.This movement of the ratchet wheel is transferred to. the sleeve throughthe co-operating bevel gear-wheel and these elements are so selectedthat the sleeve is angularly rotated by a distance (i. e. V1 revolutionper stroke) such as to reload the spring to the same extent that it wasunloaded by the previous feeding action. The

casing 2 is anchored to the support by studs 28 one of which is visiblein Fi e 1.

As has been previously stated, there is relative movement between thegun-barrel and the cylindrical casing in the direction of the axis ofthe gun-barrel and although the extent of relative movement might, intheory, be considered substantially constant, nevertheless in practice,especially where the gun is carried by an aircraft, there may be someconsiderable difference to in the extent of this relative movement. Inthe particular example being described, the gun barrel is so mounted asto be capable of movingap proximately m./m. in one direction relativelyto the cylindrical casing 2, but owing to movement of the parts of theair frame itself, which frequently happens, this relativemovement doesnot always amount to as much as 20 m./m. It

nism should be so designed as to allow the spring to be rewound to thedesired extent on each recoil (even though the amount of relativemovement is only about half of the 20 m./m.)',.and yet at the same timeto prevent overwinding if the full 20 m./m. relative movement occurs.This possible variation in the extent of movement between thecylindrical casing and the gun-barrel is allowed for by providing theswinging member with the cam face 24 which is inclined to a radial line(e. g. the line :r:-y Figure l) drawn from the-axis about which th':member 2| swings tangential to that side of the roller which is ad'-jacent to the. swinging member, the disposition andinclination .of saidcam face being such that as the roller "moves on its operative strokethe member swings through an angle proportional to positions of theroller and casing and then draw another roller position 12 m./m. fromthe initial position. At this second position the comer I assess:

the rate of linear movement of the roller plus an increment due to therelative movement of said roller along said cam face.

By this arrangement it. will be appreciated that a the cam roller 25movestowards-the cylindrical casing 2, the inclined cam face 24 willturnas the member 2| swings around the axis of the spindle At the same timethe effective radius of the member 2| will become smaller as the contactpoint between the roller and the member moves up the cam face 24 andthus the swinging member will move for a time through an increasing'angular distance for each unit of relative linear movement between thegun-barrel and the casing The rate of angular movement per unit oflinear movement will, however, begin to decrease again as the rollerreaches the end of the face 24. I I

In the construction described the inclined cam face 24 is of such alength that when the relative movement lengthwise of the gun barrel fromthe commencement of the recoil amounts to 12 m./m. the swinging member imoved through an angle about the axis of the spindle l1 sufficient tocause the ratchet wheel to move a distance of one tooth, and the camroller is at the end of this 12 m./m. movement in engagement with theend of the inclined face, that is the roller contacts with the corner orjunction formed by'the meeting of the cam face 24 and another cam face29 of the member 2|:

The angle of inclination between the cam face and the above mentionedradial line drawn from the axis-of oscillation of the swinging memberwill depend upon the stroke which it is desired shall be effective tocause the ratchet wheel to move a distance of one tooth. For instance,where it is decided, as in the present example, that a relative movementof 12 m./m.- shall be the distance necessary to turn the ratchet wheelone tooth the angle of inclination of the cam face 24 may be obtained asfollows: Set out the initial formed by the junction between the camfaces 24 and 29 should contact the roller and then by transferring thepartial shape of the member 2| thus obtained back to the initialposition a line may be drawn from the corner tangential to the roller insaid first position. This line is at the desired angle of inclination.It will be understood that the cam face need not be a flat face;

' the face could be made suitably curved along its is, therefore,important that the reloading mecha v length. It would of-course still beconsidered as inclined to the radial line mentioned above. The angle ofthe face 24 will depend upon a number of varying factors, for examplethe amount of an ular movement required by the swinging member to effecta stroke of one tooth, the diameter of the cam roller and the size anddisposition of the roller and the casing. From this data it will bestantially parallel to the aforesaid radial line from the centre of itsaxis of rotation. Thus, any continued relative-movement between thegun-barrel and cylindrical casing will cause a proportionately smallerswinging movement of the swinging member than was obtained when the camroller was acting on-the inclined face 24. Therefore, taking the presentexample, when the roller and cylindrical casing have moved a relativedistance of 12 m./m., the swinging member will have moved through anangle sufficient to have caused the ratchet wheel to have moved throughthe distance of one tooth, but a further or 12 m./m. movement betweenthe two would not cause the swinging member to move through acorresponding angle. The angle would be much smaller forthe last 10 or12 m./m. This angle would be considerably less than the distance of onetooth and accordingly it is not possible with this construction tooverwind permanently, since the further movement of a part of a toothwould immediately be cancelled out as soon as the gungagement with thecartridge case. Immediately after this the cartridges fall out of thegrooves of the sprocket wheels and pass into a trough or chute 3'! andtilt nose downwards as they apbarrel had moved forward again after itsrecoil stroke.

The spring H, a previously stated, is suitably tensioned prior to thegun being put into action and due to the rewinding apparatus abovedescribed, the spring is again fully loaded after each feeding movement.In order initially to load the spring, means to permit manual rotationof the ratchet wheel may be provided on the spindle which supports theratchet wheel. This means may comprise the shaping of the projecting endof the spindle at 39 in a manner such that a spanner can be appliedthereto, or in a more convenient method, the swinging member may be'extended as shown by the chain lines Figure 1 and provided with anaperture into which a bar 3| may be inserted to permit manualoscillation of the swinging member.

In order to prevent initial overwinding of the spring, when a bar isemployed, the bar may be split and a suitable spring urged frictionclutch provided between the two parts of the bar. The loading of thespring clutch can be such as to equal the desired maximum loading of thespring, so that when the bar has wound the spring sumciently, anyfurther actuation of the bar will cause the spring clutch on it to slipand so prevent overwinding.

While some of the devices shown in the drawings but not previouslydescribed, such for example as the devices for feeding anddisintegrating the belt, form no part of the present invention, a

brief reference thereto is thought desirable for clarity. It will beobserved from the drawings that the end plate 1 has a projecting portion36 concentric with its centre extending around a part of thecircumference. The interior of said projection constitutes a crown camwhereby the cartridges are gradually pushed lengthwise of the casing asthey travel round on the feeding elements H. As the clips 4 areconstrained by one of the sprockets II from moving lengthwise with thecartridges 5, the latter are gradually slid along the clips until theclips can fall away from the cartridges and down the chute 6. In Figure1 the cartridge has moved about half of its travel around the casing andthe left hand part of the clip 4 is therefore already almost free-fromenproach the axis of the barrel whereupon the breech mechanism closesand pushes the cartridge into the breech. These various movements arecontrolled by sundry fingers and other devices mounted on the hubs ofthe elements it but omitted from the drawings. A cam 38 is fixed to theend plate 8 and co-operates with the cam 36 to control the cartridgesduring their axial movement.

L What I claim as my invention and desire to secure by Letters Patentis: In a cartridge feeding mechanism for automatic guns of the typeprovided with a recoiling gun member and feeding mechanism for supplyingcartridges to the gun breech, including spring means adapted to be woundby relative movei ment of the recoiling member and feeding mechanism foractuating the latter, the combination with rotatable winding mechanismfor said spring means including a pawl and ratchet device, ofcooperating means on said gun member and said winding mechanism forsuccessively advancing said pawl and ratchet device through'a strokethan during an earlier portion of the stroke v of the same length, saidcam face being provided with two portions which are engaged successivelyby the follower, the first said portion of the cam face being-inclinedto a radial line drawn from the axis of the swinging member to thedriving side of said follower and located between said axis and the partof the follower which engages the first said portion of the face, theparts being so constructed and arranged that during a predeterminedinitial movement of the follower, the distance between the latter andthe axis of the swinging member is reduced, the length of the first saidportion of the cam face being such that the follower engages the secondportion of the cam face after the follower has moved said predetermineddistance relatively to the cartridge feeding mechanism, the secondportion of said cam face being so constructed and arranged that anycontinued relative movement of the follower will cause less swingingmovement of the swinging member than is effected by said first portionof said cam face.

CHARLES, THOMAS HALL.

